List of errors. The caller may supply an empty list before calling Compile; the processor will then populate the list with error information obtained during the schema compilation. Each error will be included as an object of type StaticError. If no error list is supplied by the caller, error information will be written to the standard error stream.
By supplying a custom List with a user-written add() method, it is possible to intercept error conditions as they occur.
Note that this error list is used only for errors detected while using the schema to validate a source document. It is not used to report errors in the schema itself.